In contrast, the European Union's "Privacy and Electronic Communications Directive" restricts websites' ability to use consumer data much more comprehensively. The EU limitations restrict targeting by online advertisers; researchers have estimated online advertising effectiveness decreases on average by around 65% in Europe relative to the rest of the world.[60]:58
Search engine optimization is a key part of online marketing because search is one of the primary ways that users navigate the web. In 2014, over 2.5 trillion searches were conducted worldwide across search engines such as Google, Bing, Yahoo, Baidu, and Yandex. For most websites, traffic that comes from search engines (known as "natural" or "organic" traffic) accounts for a large portion of their total traffic.

Video Marketing